regulator: axp20x: fix LDO2/4 description

Currently we wrongly set the mask of value of LDO2/4 both to the mask of
LDO2, and the LDO4 voltage configuration is left untouched. This leads
to conflict when LDO2/4 are both in use.

Fix this issue by setting different vsel_mask to both regulators.

Fixes: db4a555f

 ("regulator: axp20x: use defines for masks")
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Link: https://lore.kernel.org/r/20200923005142.147135-1-icenowy@aosc.io
Signed-off-by: Mark Brown <broonie@kernel.org>